Re: [PATCH 09/15] s390x: protvirt: SCLP interpretation

[Janosch Frank <frankja@linux.ibm.com>]

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On 11/21/19 3:11 PM, Cornelia Huck wrote:
> On Wed, 20 Nov 2019 06:43:28 -0500
> Janosch Frank <frankja@linux.ibm.com> wrote:
> 
>> SCLP for a protected guest is done over the SIDAD, so we need to use
>> the s390_cpu_virt_mem_* functions to access the SIDAD instead of guest
>> memory when reading/writing SCBs.
>>
>> To not confuse the sclp emulation, we set 0x42000 as the address, but
>> ignore it for reading/writing the SCCB.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>  hw/s390x/sclp.c         | 16 ++++++++++++++++
>>  include/hw/s390x/sclp.h |  2 ++
>>  target/s390x/kvm.c      |  8 +++++++-
>>  3 files changed, 25 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
>> index f57ce7b739..00d08adc7f 100644
>> --- a/hw/s390x/sclp.c
>> +++ b/hw/s390x/sclp.c
>> @@ -193,6 +193,22 @@ static void sclp_execute(SCLPDevice *sclp, SCCB *sccb, uint32_t code)
>>      }
>>  }
>>  
>> +int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb,
>> +                                uint32_t code)
>> +{
>> +    SCLPDevice *sclp = get_sclp_device();
>> +    SCLPDeviceClass *sclp_c = SCLP_GET_CLASS(sclp);
>> +    SCCB work_sccb;
>> +    hwaddr sccb_len = sizeof(SCCB);
>> +
>> +    s390_cpu_virt_mem_read(env_archcpu(env), 0, 0, &work_sccb, sccb_len);
>> +    sclp_c->execute(sclp, &work_sccb, code);
>> +    s390_cpu_virt_mem_write(env_archcpu(env), 0, 0, &work_sccb,
>> +                            be16_to_cpu(work_sccb.h.length));
>> +    sclp_c->service_interrupt(sclp, sccb);
>> +    return 0;
>> +}
>> +
>>  int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code)
>>  {
>>      SCLPDevice *sclp = get_sclp_device();
>> diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h
>> index c54413b78c..c0a3faa37d 100644
>> --- a/include/hw/s390x/sclp.h
>> +++ b/include/hw/s390x/sclp.h
>> @@ -217,5 +217,7 @@ void s390_sclp_init(void);
>>  void sclp_service_interrupt(uint32_t sccb);
>>  void raise_irq_cpu_hotplug(void);
>>  int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code);
>> +int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb,
>> +                                uint32_t code);
>>  
>>  #endif
>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>> index 58251c0229..0f2458b553 100644
>> --- a/target/s390x/kvm.c
>> +++ b/target/s390x/kvm.c
>> @@ -1172,7 +1172,13 @@ static int kvm_sclp_service_call(S390CPU *cpu, struct kvm_run *run,
>>      sccb = env->regs[ipbh0 & 0xf];
>>      code = env->regs[(ipbh0 & 0xf0) >> 4];
>>  
>> -    r = sclp_service_call(env, sccb, code);
>> +    if (run->s390_sieic.icptcode == ICPT_PV_INSTR ||
>> +        run->s390_sieic.icptcode == ICPT_PV_INSTR_NOT) {
>> +        r = sclp_service_call_protected(env, 0x42000, code);
> 
> I fear that confuses the reader instead of the emulation :)
> 
> Especially as you end up passing that value to
> sclp_c->service_interrupt()...

Pierre has some more opinions on that, so I'll let him present his
planned changes to this patch :)

> 
>> +    } else {
>> +        r = sclp_service_call(env, sccb, code);
>> +    }
>> +
>>      if (r < 0) {
>>          kvm_s390_program_interrupt(cpu, -r);
>>      } else {
> 



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